Pharmaceutical Composition Comprising (1r,4r)-6&#39;-fluoro-N, N-dimethyl-4-phenyl-4,9&#39; -dihydro-3&#39;H-spiro[cyclohexane-1,1&#39; -pyrano[3,4,b]indol]-4-amine and an Anticonvulsant

ABSTRACT

The invention relates to a pharmaceutical composition comprising a first pharmacologically active ingredient selected from (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine and the physiologically acceptable salts thereof, and a second pharmacologically active ingredient which is an anticonvulsant selected from the group consisting of retigabin, lamotrigine, lacosamide, levetiracetam, carbamazepine, sultiame, phenacemide, felbamate, topiramate, pheneturide, brivaracetam, selectracetam, zonisamide, stiripentol, beclamide, mexiletin, ralfinamide, methylphenobarbital, phenobarbital, primidone, barbexaclone, metharbital, ethotoin, phenyloin, amino(diphenylhydantoin) valeric acid, mephenyloin, fosphenyloin, paramethadione, trimethadione, ethadione, ethosuximide, phensuximide, mesuximide, clonazepam, lorazepam, diazepam, clobazam, oxcarbazepine, eslicarbazepine, rufinamide, valproic acid, valpromide, aminobutyric acid, progabide, tiagabine, and the physiologically acceptable salts thereof.

The invention relates to a pharmaceutical composition comprising a firstpharmacologically active ingredient selected from(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof, and a secondpharmacologically active ingredient which is an anticonvulsant selectedfrom the group consisting of retigabin, lamotrigine, lacosamide,levetiracetam, carbamazepine, sultiame, phenacemide, felbamate,topiramate, pheneturide, brivaracetam, selectracetam, zonisamide,stiripentol, beclamide, mexiletin, ralfinamide, methylphenobarbital,phenobarbital, primidone, barbexaclone, metharbital, ethotoin,phenyloin, amino(diphenylhydantoin) valeric acid, mephenyloin,fosphenyloin, paramethadione, trimethadione, ethadione, ethosuximide,phensuximide, mesuximide, clonazepam, lorazepam, diazepam, clobazam,oxcarbazepine, eslicarbazepine, rufinamide, valproic acid, valpromide,γ-aminobutyric acid, progabide, tiagabine, and the physiologicallyacceptable salts thereof.

(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]-indol]-4-amineand its corresponding physiologically acceptable salts as well asmethods for their preparation are well known, for example, fromWO2004/043967 and WO2008/040481. The compounds exhibit analgesicproperties and are particularly suitable for the treatment of acute,visceral, neuropathic or chronic (nociceptive) pain.

Anticonvulsant drugs, such as retigabin, lamotrigine, lacosamide,levetiracetam and carbamazepine are used for the treatment of variousneurological and psychiatric disorders.

Though both of the aforementioned substance classes are therapeuticallyeffective, side effects may occur, especially upon prolonged use or whenadministered at high dosages.

It is further known that specific combinations of pharmacologicallyactive compounds exert supra-additive (synergistic) therapeutic effectsupon administration. An advantage of these special cases is that theoverall dose and accordingly the risk of undesired side effects may bereduced.

In a further aspect, two pharmacologically active compounds exerting asynergistic effect may be combined in one single pharmaceutical dosageform, e.g. a tablet, thus enhancing patient compliance.

It is an object of the invention to provide pharmaceutical compositionswhich have advantages compared to pharmaceutical compositions of theprior art. In particular, the pharmaceutical compositions should providerapid therapeutic effects, but also should have a high tolerability,good compliance and safety.

This object has been achieved by the subject-matter of the patentclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows % MPE in dependence of the time elapsed afteradministration.

FIG. 2 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and carbamazepine as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

FIG. 3 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and carbamazepine as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

FIG. 4 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and levetiracetam as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

FIG. 5 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and lacosamide as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

FIG. 6 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and retigabine as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

It has been surprisingly found that a pharmaceutical compositioncomprising(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand an anticonvulsant drug, such as retigabin, is useful for thetreatment of pain, especially chronic pain, in particular neuropathicpain.

Further it has been surprisingly found that said composition exhibits asynergistic therapeutic effect upon administration. Therefore, theoverall administered dose may be lowered, so that fewer undesiredside-effects will occur.

A first aspect of the invention relates to a pharmaceutical compositioncomprising:

-   -   (a) a first pharmacologically active ingredient selected from        (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine        and the physiologically acceptable salts thereof, and    -   (b) a second pharmacologically active ingredient which is an        anticonvulsant selected from the group consisting of retigabin,        lamotrigine, lacosamide, levetiracetam, carbamazepine, sultiame,        phenacemide, felbamate, topiramate, pheneturide, brivaracetam,        selectracetam, zonisamide, stiripentol, beclamide, mexiletin,        ralfinamide, methylphenobarbital, phenobarbital, primidone,        barbexaclone, metharbital, ethotoin, phenyloin,        amino(diphenylhydantoin) valeric acid, mephenyloin,        fosphenyloin, paramethadione, trimethadione, ethadione,        ethosuximide, phensuximide, mesuximide, clonazepam, lorazepam,        diazepam, clobazam, oxcarbazepine, eslicarbazepine, rufinamide,        valproic acid, valpromide, γ-aminobutyric acid, progabide,        tiagabine, and the physiologically acceptable salts thereof.

The pharmaceutical composition according to the invention comprises afirst pharmacologically active ingredient selected from(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof.

For the purpose of specification,(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineis the compound according to formula (I) which can also be referred toas1,1-(3-dimethylamino-3-phenylpentamethylene)-6-fluoro-1,3,4,9-tetrahydropyrano[3,4-b]indole(trans)

The definition of the first pharmacologically active ingredient includes(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano-[3,4,b]indol]-4-aminein form of the free base, i.e. the compound according to formula (I), inany possible form including solvates, cocrystals and polymorphs, and itsphysiologically acceptable salts, in particular acid addition salts andcorresponding solvates, cocrystals and polymorphs.

The pharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminemay be present in the pharmaceutical composition according to theinvention in form of a physiologically acceptable salt, preferably anacid addition salt, whereby any suitable acid capable of forming such anaddition salt may be used.

The conversion of(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclo-hexane-1,1′-pyrano[3,4,b]indol]-4-amineinto a corresponding addition salt, for example, via reaction with asuitable acid may be effected in a manner well known to those skilled inthe art. Suitable acids include but are not limited to hydrochloricacid, hydrobromic acid, sulfuric acid, methanesulfonic acid, formicacid, acetic acid, oxalic acid, succinic acid, tartaric acid, mandelicacid, fumaric acid, lactic acid, citric acid, glutamic acid and/oraspartic acid. Salt formation is preferably effected in a solvent, forexample, diethyl ether, diisopropyl ether, alkyl acetates, acetoneand/or 2-butanone. Moreover, trimethylchlorosilane in aqueous solutionis also suitable for the preparation of hydrochlorides.

In a preferred embodiment, the first pharmacologically active ingredientis(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the free base, i.e. the compound according to formula (I).

In another preferred embodiment, the first pharmacologically activeingredient is (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine in form of aphysiologically acceptable acid addition salt, in particular thehydrochloride, hemicitrate or maleate salt.

Unless explicitly stated otherwise, all amounts of the firstpharmacologically active ingredient specified in the following are givenaccording to the corresponding amount of(1r,40-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the free base, i.e. the compound according to formula (I).

The pharmaceutical composition according to the invention comprises asecond pharmacologically active ingredient which is an anticonvulsantselected from the group consisting of retigabin, lamotrigine,lacosamide, levetiracetam, carbamazepine, sultiame, phenacemide,felbamate, topiramate, pheneturide, brivaracetam, selectracetam,zonisamide, stiripentol, beclamide, mexiletin, ralfinamide,methylphenobarbital, phenobarbital, primidone, barbexaclone,metharbital, ethotoin, phenyloin, amino(diphenylhydantoin) valeric acid,mephenyloin, fosphenyloin, paramethadione, trimethadione, ethadione,ethosuximide, phensuximide, mesuximide, clonazepam, lorazepam, diazepam,clobazam, oxcarbazepine, eslicarbazepine, rufinamide, valproic acid,valpromide, γ-aminobutyric acid, progabide, tiagabine, and thephysiologically acceptable salts thereof.

The definition of the second pharmacologically active ingredientincludes the aforementioned anticonvulsants in any possible formincluding any enantiomers, if applicable, solvates, prodrugs, cocrystalsand polymorphs, and their physiologically acceptable salts, inparticular acid addition salts and corresponding solvates, cocrystalsand polymorphs.

Physiologically acceptable salts include the corresponding acid additionsalts as well as the corresponding metal salts, if applicable. This maybe effected in a manner well known to those skilled in the art, forexample, via reaction with a suitable acid or via reaction with asuitable base or metal salt, respectively. Suitable acids include butare not limited to hydrochloric acid, hydrobromic acid, sulfuric acid,methanesulfonic acid, formic acid, acetic acid, oxalic acid, succinicacid, tartaric acid, mandelic acid, fumaric acid, lactic acid, citricacid, glutamic acid and/or aspartic acid. Moreover,trimethylchlorosilane in aqueous solution is also suitable for thepreparation of hydrochlorides. Suitable bases include but are notlimited to inorganic bases, including the hydroxides of sodium,potassium, calcium, magnesium, aluminium and zinc; and organic bases,such as triethyl amine, trimethylamine, N,N-diisopropylethylamine,N-methylmorpholine, morpholine, N-methylpiperidine, imidazole andammonia. Suitable metal salts include but are not limited to alkalisalts such as sodium, potassium or lithium phosphate, sulfate,methanesulfonate, formate, acetate, oxalate, succinate, tartrate,mandelate, fumarate, lactate, citrate, glutamate, aspartate and/orsilyls, as well as alkaline earth salts, in particular magnesium andcalcium salts, including their phosphate, sulfate, methanesulfonate,formate, acetate, oxalate, succinate, tartrate, mandelate, fumarate,lactate, citrate, glutamate, aspartate and/or silyl salts. Saltformation is preferably effected in a solvent, for example, diethylether, diisopropyl ether, alkyl acetates, acetone and/or 2-butanone.

As prodrugs, amides, ethers and esters are particularly preferred.Suitable methods for selecting and preparing a prodrug of a givensubstance are, for example, described in “Textbook of Drug Design andDiscovery, 3^(rd) edition, 2002, chapter 14, pages 410-458, Editors:Krogsgaard-Larsen et al., Taylor and Francis.

In a preferred embodiment, the second pharmacologically activeingredient is selected from the group consisting of retigabin,lamotrigine, lacosamide, levetiracetam, sultiame, phenacemide,felbamate, topiramate, pheneturide, brivaracetam, selectracetam,zonisamide, stiripentol, beclamide, mexiletin, ralfinamide, and thephysiologically acceptable salts thereof.

In another preferred embodiment, the second pharmacologically activeingredient is a benzodiazepine derivative, preferably selected from thegroup consisting of lorazepam, diazepam, clonazepam, clobazam and thephysiologically acceptable salts thereof.

In still another preferred embodiment, the second pharmacologicallyactive ingredient is a barbiturate derivative, preferably selected fromthe group consisting of methylphenobarbital, phenobarbital, primidone,barbexaclone, metharbital and the physiologically acceptable saltsthereof.

In yet another preferred embodiment, the second pharmacologically activeingredient is a hydantoin derivative, preferably selected from the groupconsisting of ethotoin, phenyloin, amino(diphenylhydantoin) valericacid, mephenyloin, fosphenyloin, and the physiologically acceptablesalts thereof.

In a further preferred embodiment, the second pharmacologically activeingredient is an oxazolidine derivative, preferably selected from thegroup consisting of paramethadione, trimethadione, ethadione, and thephysiologically acceptable salts thereof.

In a preferred embodiment, the second pharmacologically activeingredient is a succinimide derivative, preferably selected from thegroup consisting of ethosuximide, phensuximide, mesuximide, and thephysiologically acceptable salts thereof.

In another preferred embodiment, the second pharmacologically activeingredient is a carboxamide derivative, preferably selected from thegroup consisting of carbamazepine, oxcarbazepine, eslicarbazepine,rufinamide, and the physiologically acceptable salts thereof.

In still another preferred embodiment, the second pharmacologicallyactive ingredient is a fatty acid derivative, preferably selected fromthe group consisting of valproic acid, valpromide, γ-aminobutyric acid,progabide, tiagabine, and the physiologically acceptable salts thereof.

In a particularly preferred embodiment, the second pharmacologicallyactive ingredient is selected from the group consisting of retigabine,lamotrigine, lacosamide, levetiracetam, and carbamazepine.

Unless explicitly stated otherwise, all amounts of the secondpharmacologically active ingredient specified in the following are givenaccording to the corresponding amount of the free compound.

In a preferred embodiment, the second pharmacologically activeingredient is retigabin or a physiologically acceptable salt thereof, inparticular a hydrochloride salt thereof; the dihydrochloride salt isespecially preferred.

In another preferred embodiment, the second pharmacologically activeingredient is retigabin.

In still another preferred embodiment, the second pharmacologicallyactive ingredient is carbamazepine or a physiologically acceptable saltthereof.

In yet another preferred embodiment, the second pharmacologically activeingredient is lamotrigine or a physiologically acceptable salt thereof.

In a further preferred embodiment, the second pharmacologically activeingredient is levetiracetam or a physiologically acceptable saltthereof.

In still a further preferred embodiment, the second pharmacologicallyactive ingredient is lacosamide or a physiologically acceptable saltthereof.

In a preferred embodiment, the first pharmacologically active ingredientis(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the free base, i.e. the compound according to formula (I),and the second pharmacologically active ingredient is retigabin.

In another preferred embodiment, the first pharmacologically activeingredient is(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the free base, i.e. the compound according to formula (I),and the second pharmacologically active ingredient is retigabin in formof a hydrochloride salt, preferably the monohydrochloride ordihydrochloride salt; retigabin dihydrochloride is especially preferred.

In still another preferred embodiment, the first pharmacologicallyactive ingredient is(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of a physiologically acceptable acid addition salt, inparticular the hydrochloride, hemicitrate or maleate salt, and thesecond pharmacologically active ingredient is retigabin.

In a further preferred embodiment, the first pharmacologically activeingredient is(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of a physiologically acceptable acid addition salt, inparticular the hydrochloride, hemicitrate or maleate salt, and thesecond pharmacologically active ingredient is retigabin in form of ahydrochloride salt, preferably the monohydrochloride or dihydrochloridesalt; retigabin dihydrochloride is especially preferred.

In case that the second pharmacologically active ingredient contains anacidic group, such as a carboxyl or amide group, it may react with thefirst pharmacologically active ingredient according to formula (I)forming a salt which incorporates both pharmacologically activeingredients.

Thus, in another preferred embodiment, the pharmaceutical compositionaccording to the invention comprises the first and the secondpharmacologically active ingredient in form of a salt formed from thesetwo pharmacologically active ingredients. Such a salt formation may bepartial, i.e. the pharmaceutical composition according to the inventioncomprises one or both of these pharmacologically active ingredients alsoin their non-salt form, or the salt formation may essentially becomplete.

Another aspect of the invention relates to a pharmaceutical dosage formcomprising the pharmaceutical composition according to the invention.

The first and the second pharmacologically active ingredient aretypically contained in the pharmaceutical dosage form according to theinvention in a therapeutically effective amount. The amount thatconstitutes a therapeutically effective amount varies according to thepharmacologically active ingredients, the condition being treated, theseverity of said condition, the patient being treated, and whether thepharmaceutical dosage form is designed for an immediate or controlledrelease.

In a preferred embodiment, the content of the first pharmacologicallyactive ingredient in the pharmaceutical dosage form according to theinvention and the pharmaceutical composition according to the invention,respectively, is at most 10 wt.-% or at most 5 wt.-% or at most 3 wt.-%or at most 1.0 wt.-%, more preferably at most 0.8 wt.-%, yet morepreferably at most 0.5 wt.-%, still more preferably at most 0.2 wt.-%,even more preferably at most 0.1 wt.-%, most preferably at most 0.05wt.-%, and in particular at most 0.01 wt.-% or at most 0.005 wt.-% or atmost 0.001 wt.-%.

In a preferred embodiment, the content of the second pharmacologicallyactive ingredient in the pharmaceutical dosage form according to theinvention and the pharmaceutical composition according to the invention,respectively, is at most 95 wt.-%, more preferably at most 80 wt.-%, yetmore preferably at most 70 wt.-%, still more preferably at most 60wt.-%, even more preferably at most 55 wt.-%, most preferably at most 50wt.-%, and in particular at most 45 wt.-%.

In a preferred embodiment, in particular when the secondpharmacologically active ingredient is a benzodiazepine derivative, thecontent of the second pharmacologically active ingredient in thepharmaceutical dosage form according to the invention and thepharmaceutical composition according to the invention, respectively, isat most 40 wt.-%, still more preferably at most 20 wt.-%, even morepreferably at most 15 wt.-%, most preferably at most 10 wt.-%, and inparticular at most 5 wt.-%.

In a preferred embodiment, the content of the first pharmacologicallyactive ingredient in the pharmaceutical dosage form according to theinvention and the pharmaceutical composition according to the invention,respectively, is at least 0.0001 wt.-%, more preferably at least 0.0003wt.-%, yet more preferably at least 0.0005 wt.-%, still more preferablyat least 0.0008 wt.-%, even more preferably at least 0.001 wt.-%, mostpreferably at least 0.003 wt.-%, and in particular at least 0.005 wt.-%.

In a preferred embodiment, the content of the second pharmacologicallyactive ingredient in the pharmaceutical dosage form according to theinvention and the pharmaceutical composition according to the invention,respectively, is at least 0.001 wt.-%, more preferably at least 0.003wt.-%, yet more preferably at least 0.005 wt.-%, still more preferablyat least 0.001 wt.-%, even more preferably at least 0.1 wt.-%, mostpreferably at least 0.3 wt.-%, and in particular at least 0.5 wt.-%.

In a preferred embodiment, the content of the second pharmacologicallyactive ingredient in the pharmaceutical dosage form according to theinvention and the pharmaceutical composition according to the invention,respectively, is at least 0.1 wt.-%, more preferably at least 0.5 wt.-%,yet more preferably at least 1 wt.-%, still more preferably at least 3wt.-%, even more preferably at least 5 wt.-%, most preferably at least7.5 wt.-%, and in particular at least 10 wt.-%.

Unless explicitly stated otherwise, in the meaning of the invention theindication “wt.-%” shall mean weight of the respective ingredient pertotal weight of the pharmaceutical dosage form or per total weight ofthe pharmaceutical composition, respectively.

Preferably, in the pharmaceutical dosage form according to the inventionand the pharmaceutical composition according to the invention,respectively, the relative weight ratio of the first pharmacologicallyactive ingredient to the second pharmacologically active ingredient iswithin the range of from 1:2 to 1:100,000,000, and more preferably 1:5to 1:1,000,000 or 100,000.

In a preferred embodiment, in particular when the secondpharmacologically active ingredient is a benzodiazepine derivative, inthe pharmaceutical dosage form according to the invention and thepharmaceutical composition according to the invention, respectively, therelative weight ratio of the first pharmacologically active ingredientto the second pharmacologically active ingredient is within the range offrom 1:2 to 1:2,000, more preferably 1:3 to 1:1,500, still morepreferably 1:4 to 1:1,000, most preferably 1:5 to 1:750, and inparticular 1:5 to 1:100 or 1:100 to 1:750.

In another preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative weight ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:100 to 1:10,000, morepreferably 1:200 to 1:7,500, still more preferably 1:500 to 1:5,000,most preferably 1:750 to 1:2,500, and in particular 1:900 to 1:2,000.

In still another preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative weight ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:1,000 to 1:100,000, morepreferably 1:2,000 to 1:80,000, still more preferably 1:4,000 to1:50,000, yet more preferably 1:6,000 to 1:20,000, most preferably1:8,000 to 1:15,000, and in particular 1:9,000 to 1:12,500.

In yet another preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative weight ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:5,000 to 1:500,000, morepreferably 1:10,000 to 1:400,000, still more preferably 1:20,000 to1:300,000, most preferably 1:40,000 to 1:250,000, and in particular1:50,000 to 1:200,000.

In a further preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative weight ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:100,000 to 1:1,900,000,more preferably 1:250,000 to 1:1,800,000, still more preferably1:300,000 to 1:700,000, most preferably 1:350,000 to 1:650,000, and inparticular 1:400,000 to 1:600,000.

In a still further preferred embodiment, in the pharmaceutical dosageform according to the invention and the pharmaceutical compositionaccording to the invention, respectively, the relative weight ratio ofthe first pharmacologically active ingredient to the secondpharmacologically active ingredient is within the range of from1:100,000 to 1:1,000,000, more preferably 1:250,000 to 1:980,000, stillmore preferably 1:500,000 to 1:960,000, most preferably 1:600,000 to1:950,000, and in particular 1:700,000 to 1:900,000.

Preferably, in the pharmaceutical dosage form according to the inventionand the pharmaceutical composition according to the invention,respectively, the relative molar ratio of the first pharmacologicallyactive ingredient to the second pharmacologically active ingredient iswithin the range of from 1:2 to 1:1,000,000, and more preferably 1:5 to1:100,000.

In a preferred embodiment, in particular when the secondpharmacologically active ingredient is a benzodiazepine derivative, inthe pharmaceutical dosage form according to the invention and thepharmaceutical composition according to the invention, respectively, therelative molar ratio of the first pharmacologically active ingredient tothe second pharmacologically active ingredient is within the range offrom 1:2 to 1:2,000, more preferably 1:3 to 1:1,500, still morepreferably 1:4 to 1:1,000, most preferably 1:5 to 1:750, and inparticular 1:5 to 1:100 or 1:100 to 750.

In another preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative molar ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:100 to 1:10,000, morepreferably 1:200 to 1:7,500, still more preferably 1:500 to 1:5,000,most preferably 1:750 to 1:2,500, and in particular 1:900 to 1:2,000.

In still another preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative molar ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:1,000 to 1:100,000, morepreferably 1:2,000 to 1:80,000, still more preferably 1:4,000 to1:50,000, yet more preferably 1:6,000 to 1:20,000, most preferably1:8,000 to 1:15,000, and in particular 1:9,000 to 1:12,500.

In yet another preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative molar ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:5,000 to 1:500,000, morepreferably 1:10,000 to 1:400,000, still more preferably 1:20,000 to1:300,000, most preferably 1:40,000 to 1:250,000, and in particular1:50,000 to 1:200,000.

In a further preferred embodiment, in the pharmaceutical dosage formaccording to the invention and the pharmaceutical composition accordingto the invention, respectively, the relative molar ratio of the firstpharmacologically active ingredient to the second pharmacologicallyactive ingredient is within the range of from 1:100,000 to 1:1,900,000,more preferably 1:250,000 to 1:1,800,000, still more preferably1:300,000 to 1:700,000, most preferably 1:350,000 to 1:650,000, and inparticular 1:400,000 to 1:600,000.

In a still further preferred embodiment, in the pharmaceutical dosageform according to the invention and the pharmaceutical compositionaccording to the invention, respectively, the relative molar ratio ofthe first pharmacologically active ingredient to the secondpharmacologically active ingredient is within the range of from1:100,000 to 1:1,000,000, more preferably 1:250,000 to 1:980,000, stillmore preferably 1:500,000 to 1:960,000, most preferably 1:600,000 to1:950,000, and in particular 1:700,000 to 1:900,000.

The amounts of the first and the second pharmacologically activeingredient contained in the pharmaceutical dosage form according to theinvention may vary depending on different factors well known to thoseskilled in the art, for example, the weight of the patient, the route ofadministration, the severity of the illness and the like.

In general, both pharmacologically active ingredients contained in thepharmaceutical dosage form according to the invention may beadministered in amounts up to their maximum daily dose, which is knownto those skilled in the art. For example, as the secondpharmacologically active ingredient, retigabin may preferably beadministered to a patient in a maximum daily dose of up to 1,200 mg,whereas lorazepam may preferably only be administered to a patient in amaximum daily dose of up to 7.5 mg, and felbamate may preferably beadministered to a patient in a maximum daily dose of up to 2,400 mg.

When administered in the prescribed manner, e.g. once daily or twicedaily, the pharmaceutical dosage form according to the invention and thepharmaceutical composition according to the invention, respectively,preferably contain the first and the second pharmacologically activeingredient, independently of one another, in an amount corresponding to75±15 wt.-%, 75±10 wt.-%, 75±5 wt.-%, 50±15 wt.-%, 50±10 wt.-%, 50±5wt.-%, 25±15 wt.-%, 25±10 wt.-% or 25±5 wt.-% of the respective maximumdaily dose of the first and the second pharmacologically activeingredient, respectively.

Preferably, the pharmaceutical dosage form according to the inventioncontains the first pharmacologically active ingredient in a dose of from0.1 μg to 5,000 μg, more preferably, 0.1 μg to 2,500 μg, still morepreferably 1.0 μg to 1,000 μg, yet more preferably 10 to 800 μg, mostpreferably 15 μg to 600 μg, and in particular 20 μg to 440 μg.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention contains the first pharmacologically active ingredient ina dose within the range of 13±12 μg, more preferably 13±10 μg, stillmore preferably 13±8 μg, yet more preferably 13±6 μg, even morepreferably 13±5 μg, most preferably 13±4 μg, and in particular 13±3 μg.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 20±15 μg, more preferably 20±13μg, still more preferably 20±12 μg, yet more preferably 20±10 μg, evenmore preferably 20±8 μg, most preferably 20±6 μg, and in particular 20±5μg.

In still another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 40±35 μg, more preferably 40±30μg, still more preferably 40±25 μg, yet more preferably 40±20 μg, evenmore preferably 40±15 μg, most preferably 40±10 μg, and in particular40±5 μg.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 60±50 μg, more preferably 60±40μg, still more preferably 60±30 μg, yet more preferably 60±20 μg, mostpreferably 60±10 μg, and in particular 60±5 μg.

In a further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 80±70 μg, more preferably 80±60μg, still more preferably 80±50 μg, yet more preferably 80±40 μg, evenmore preferably 80±20 μg, most preferably 80±10 μg, and in particular80±5 μg.

In still a further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 100±90 μg, more preferably100±80 μg, still more preferably 100±60 μg, yet more preferably 100±40μg, even more preferably 100±20 μg, most preferably 100±10 μg, and inparticular 100±5 μg.

In yet a further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 120±100 μg, more preferably120±80 μg, still more preferably 120±60 μg, yet more preferably 120±40μg, even more preferably 120±20 μg, most preferably 120±10 μg, and inparticular 120±5 μg.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 150±90 μg, more preferably150±80 μg, still more preferably 150±60 μg, yet more preferably 150±40μg, even more preferably 150±20 μg, most preferably 150±10 μg, and inparticular 150±5 μg.

In still another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 170±130 μg, more preferably170±100 μg, still more preferably 170±80 μg, yet more preferably 170±60μg, even more preferably 170±40 μg, most preferably 170±20 μg, and inparticular 170±10 μg.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 200±175 μg, more preferably200±150 μg, still more preferably 200±125 μg, yet more preferably200±100 μg, even more preferably 200±75 μg, most preferably 200±50 μg,and in particular 200±25 μg.

In a further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 400±350 μg, more preferably400±300 μg, still more preferably 400±250 μg, yet more preferably400±200 μg, even more preferably 400±150 μg, most preferably 400±100 μg,and in particular 400±50 μg.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 600±400 μg, more preferably600±300 μg, still more preferably 600±250 μg, yet more preferably600±200 μg, even more preferably 600±150 μg, most preferably 600±100 μg,and in particular 600±50 μg.

In still another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 800±550 μg, more preferably800±400 μg, still more preferably 800±350 μg, yet more preferably800±250 μg, even more preferably 800±150 μg, most preferably 800±100 μg,and in particular 800±50 μg.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 1,000±800 μg, more preferably1,000±600 μg, still more preferably 1,000±500 μg, yet more preferably1,000±300 μg, even more preferably 1,000±200 μg, most preferably1,000±100 μg, and in particular 1,000±50 μg.

In a further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the first pharmacologically activeingredient in a dose within the range of 1,200±1,000 μg, more preferably1,200±800 μg, still more preferably 1,200±600 μg, yet more preferably1,200±400 μg, even more preferably 1,200±200 μg, most preferably1,200±100 μg, and in particular 1,200±50 μg.

Preferably, the pharmaceutical dosage form according to the inventioncontains the second pharmacologically active ingredient in a dose offrom 0.01 mg to 7,500 mg, more preferably, 0.05 mg to 6,000 mg, stillmore preferably 0.1 mg to 5,000 mg, most preferably 0.5 mg to 4,000 mg,and in particular 1.0 mg to 3,000 mg.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention contains the second pharmacologically active ingredient ina dose within the range of 0.005 to 300 mg, more preferably 0.01 to 200mg, still more preferably 0.05 to 150 mg, yet more preferably 0.1 to 100mg, even more preferably 0.5 to 80 mg, most preferably 0.75 to 60 mg,and in particular 1.0 to 40 mg.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the second pharmacologically activeingredient in a dose within the range of 300±250 mg, more preferably300±200 mg, still more preferably 300±150 mg, yet more preferably300±125 mg, even more preferably 300±100 mg, most preferably 300±75 mg,and in particular 300±50 mg.

In still another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the second pharmacologically activeingredient in a dose within the range of 500±400 mg, more preferably500±300 mg, still more preferably 500±200 mg, yet more preferably500±150 mg, even more preferably 500±100 mg, most preferably 500±75 mg,and in particular 500±50 mg.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the second pharmacologically activeingredient in a dose within the range of 750±500 mg, more preferably750±400 mg, still more preferably 750±250 mg, yet more preferably750±100 mg, even more preferably 750±75 mg, most preferably 750±50 mg,and in particular 750±25 mg.

In a further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the second pharmacologically activeingredient in a dose within the range of 1,000±500 mg, more preferably1,000±400 mg, still more preferably 1,000±250 mg, yet more preferably1,000±100 mg, even more preferably 1,000±75 mg, most preferably 1,000±50mg, and in particular 1,000±25 mg.

In a still further preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the second pharmacologically activeingredient in a dose within the range of 1,500±500 mg, more preferably1,500±400 mg, still more preferably 1,500±250 mg, yet more preferably1,500±100 mg, even more preferably 1,500±75 mg, most preferably 1,500±50mg, and in particular 1,500±25 mg.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention contains the second pharmacologically active ingredient ina dose within the range of 1,800±1,000 mg, more preferably 1,800±750 mg,still more preferably 1,800±500 mg, yet more preferably 1,800±300 mg,even more preferably 1,800±200 mg, most preferably 1,800±100 mg, and inparticular 1,800±50 mg.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention contains the second pharmacologically activeingredient in a dose within the range of 2,000±1,000 mg, more preferably2,000±750 mg, still more preferably 2,000±500 mg, yet more preferably2,000±300 mg, even more preferably 2,000±200 mg, most preferably2,000±100 mg, and in particular 2,000±50 mg.

In a preferred embodiment, the pharmaceutical dosage form containsretigabine or a physiologically acceptable salt thereof as the secondpharmacologically active ingredient in a dose within the range of 200 mgto 1,500 mg, more preferably in the range of 300 mg to 1,400 mg, evenmore preferably in the range of 400 mg to 1,300 mg, most preferably inthe range of 500 mg to 1,200 mg and in particular in the range of 600 mgto 1,000 mg.

In the pharmaceutical dosage form according to the invention, the doseof the first pharmacologically active ingredient is preferably withinthe range of from 1:20 to 20:1 of the amount which is equieffective tothe dosage of the second pharmacologically active ingredient. In thisregard, “equieffective” preferably means the dosage that would berequired in order to achieve the equivalent desired therapeutic effectwhen being administered alone. A skilled person recognizes that when thedesired therapeutic effect is an analgesic effect, the equieffectivedosage is determined with respect to the analgesic properties of thefirst pharmacologically active ingredient and the second pharmacologicalingredient.

For example, when the dose of the second pharmacologically activeingredient, which is contained in the pharmaceutical dosage formaccording to the invention, amounts to e.g. 30 mg and provides ananalgesic effect E when being administered alone at this dose, and whenthe equieffective amount of the first pharmacologically activeingredient, i.e. the amount needed in order to provide the sameanalgesic effect E when being administered alone, would be e.g. 4 μg,the dosage of the first pharmacologically active ingredient, which iscontained in the pharmaceutical dosage form according to the invention,may vary from 0.2 μg (4 μg/20) to 80 μg (20/4 μg).

In a preferred embodiment, the dose of the first pharmacologicallyactive ingredient is within the range of from 1:15 to 15:1, preferablywithin the range of from 1:10 to 10:1, more preferably within the rangeof from 1:8 to 8:1, still more preferably within the range of from 1:6to 6:1, yet more preferably within the range of from 1:4 to 4:1, mostpreferably within the range of from 1:3 to 3:1, and in particularpreferably within the range of from 1:2 to 2:1, of the amount which isequieffective to the dose of the second pharmacologically activeingredient.

Suitable pathways of administration of the pharmaceutical dosage formaccording to the invention include but are not limited to oral,intravenous, intraperitoneal, intradermal, transdermal, intrathecal,intramuscular, intranasal, transmucosal, subcutaneous, local and/orrectal administration.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention is for oral administration.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention is for parenteral, in particular intravenous,intraperitoneal, intrathecal, intramuscular, or subcutaneousadministration.

The pharmaceutical dosage form according to the invention and thepharmaceutical composition according to the invention, respectively, canbe solid, semi-solid or liquid.

The pharmaceutical dosage form according to the invention and thepharmaceutical composition according to the invention, respectively, maycontain auxiliary agents, for example, carriers, fillers, solvents,diluents, colorants and/or binders. The selection of auxiliary agentsand of the amounts of the same to be used depends, for example, on howthe first and the second pharmacologically acrive ingredient are to beadministered, e.g. orally, intravenously, intraperitoneally,intradermally, transdermally, intrathecally, intramuscularly,intranasally, transmucosally, subcutaneously, rectally or locally.

Suitable auxiliary agents are in particular any substances known to aperson skilled in the art useful for the preparation of galenical dosageforms. Examples of suitable auxiliary agents include but are not limitedto: water, ethanol, 2-propanol, glycerol, ethylene glycol, propyleneglycol, polyethylene glycol, polypropylene glycol, glucose, fructose,lactose, saccharose, dextrose, molasses, starch, modified starch,gelatine, sorbitol, inositol, mannitol, microcrystalline cellulose,methyl cellulose, carboxymethyl cellulose, cellulose acetate, shellac,cetyl alcohol, polyvinyl pyrrolidone, paraffins, waxes, natural andsynthetic gums, acacia gum, alginates, dextran, saturated andunsaturated fatty acids, stearic acid, magnesium stearate, zincstearate, glycerol stearate, sodium lauryl sulphate, edible oils, sesameoil, coconut oil, peanut oil, soybean oil, lecithin, sodium lactate,polyoxyethylene and polypropylene fatty acid ester, sorbitan fatty acidester, sorbic acid, benzoic acid, citric acid, ascorbic acid, tannicacid, sodium chloride, potassium chloride, magnesium chloride, calciumchloride, magnesium oxide, zinc oxide, silicon dioxide, titanium oxide,titanium dioxide, magnesium sulphate, zinc sulphate, calcium sulphate,potash, calcium phosphate, dicalcium phosphate, potassium bromide,potassium iodide, talcum, kaolin, pectin, crosspovidone, agar andbentonite.

Pharmaceutical dosage forms which are suitable for oral administrationinclude but are not limited to tablets, ° effervescent tablets, chewingtablets, dragees, capsules, drops, juices and syrups. Oralpharmaceutical dosage forms may also be in the form of multiparticulatessuch as granules, pellets, spheres, crystals and the like, optionallycompressed into a tablet, filled into a capsule, filled into a sachet orsuspended in a suitable liquid medium. Oral pharmaceutical dosage formsmay also be equipped with an enteric coating.

Pharmaceutical dosage forms that are suitable for parenteral, topicaland inhalative administration include but are not limited to solutions,suspensions, easily reconstitutable dry preparations and sprays.

Suppositories are a suitable pharmaceutical dosage form for rectaladministration. Dosage forms in a deposit, in dissolved form, forexample, in a patch optionally with the addition of agents to promoteskin penetration, are examples of suitable dosage forms for percutaneousadministration.

In an especially preferred embodiment, the pharmaceutical dosage formaccording to the invention is a tablet.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention is for administration six times daily, five times daily,four times daily, thrice daily, twice daily, once daily, or lessfrequently.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention is for administration once daily.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention is for administration twice daily.

In a preferred embodiment, particularly when the secondpharmacologically active ingredient is carbamazepine, the pharmaceuticaldosage form according to the invention is for administration once ortwice daily.

In another preferred embodiment, particularly when the secondpharmacologically active ingredient is lamotrigine, the pharmaceuticaldosage form according to the invention is for administration once ortwice daily.

In still another preferred embodiment, particularly when the secondpharmacologically active ingredient is retigabin, the pharmaceuticaldosage form according to the invention is for administration multipledaily, in particular twice daily, thrice daily, or up to six times aday.

In yet another preferred embodiment, particularly when the secondpharmacologically active ingredient is levetiracetam, the pharmaceuticaldosage form according to the invention is for administration multipledaily, in particular twice daily, thrice daily, or up to six times aday.

In a further preferred embodiment, particularly when the secondpharmacologically active ingredient is lacosamide, the pharmaceuticaldosage form according to the invention is for administration multipledaily, in particular twice daily, thrice daily, or up to six times aday.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention is for administration thrice daily.

For the purpose of specification, “administration thrice daily” (tid)preferably means that the pharmaceutical dosage form according to theinvention is adapted for being consecutively administered according to aregimen comprising the administration of three pharmaceutical dosageforms per day, wherein the time interval between the consecutiveadministration of two pharmaceutical dosage forms is at least 3 hours,preferably at least 4 hours, more preferably not least 6 hours and inparticular, about 8 hours.

For the purpose of specification, “administration twice daily” (bid)preferably means that the pharmaceutical dosage form according to theinvention is adapted for being consecutively administered according to aregimen comprising the administration of two pharmaceutical dosage formsper day, wherein the time interval between the consecutiveadministration of two pharmaceutical dosage forms is at least 6 hours,preferably at least 8 hours, more preferably at least 10 hours and inparticular, about 12 hours.

For the purpose of specification, “administration once daily” (sid)preferably means that the pharmaceutical dosage form according to theinvention is adapted for being consecutively administered according to aregimen comprising the administration of one pharmaceutical dosage formper day, wherein the time interval between the consecutiveadministration of two pharmaceutical dosage forms is at least 18 hours,preferably at least 20 hours, more preferably at least 22 hours and inparticular, about 24 hours.

A skilled person is fully aware that the above administration regimensmay be realized by administering a single pharmaceutical dosage formcontaining the full amount of the first pharmacologically activeingredient and the full amount of the second pharmacologically activeingredient to be administered at a particular point in time or,alternatively, administering a multitude of dose units, i.e. two, threeor more dose units, the sum of which multitude of dose units containingthe full amount of the first pharmacologically active ingredient and thesecond pharmacologically active ingredient to be administered at saidparticular point in time, where the individual dose units are adaptedfor simultaneous administration or administration within a short periodof time, e.g. within 5, 10 or 15 minutes.

In the following, the doses of the first and the secondpharmacologically active ingredient are expressed according to thenumber of prescribed administrations “n” per day, i.e. the number ofadministrations of the pharmaceutical dosage form according to theinvention in the course of 24 hours. As an example, 100/n μg in case ofan administration once daily (n=1) corresponds to a dose of 100 μg, and100/n μg in case of an administration twice daily (n=2) corresponds to adose of 50 μg.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention is for administration once daily (n=1), wherein thepharmaceutical dosage form contains the first pharmacologically activeingredient in a dose of from 15/n to 100/n μg, preferably 20/n to 80/nμg, and the second pharmacologically active ingredient in a dose of from1.0/n to 2,500/n mg. According to this embodiment, the pharmaceuticaldosage form according to the invention is preferably for oraladministration, preferably in form of a tablet.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention is for administration multiple daily (n=2, 3,4, 5 or 6), wherein the pharmaceutical dosage form contains the firstpharmacologically active ingredient in a dose of from 15/n to 100/n μg,preferably 20/n to 80/n μg, and the second pharmacologically activeingredient in a dose of from 1.0/n to 2,500/n mg. According to thisembodiment, the pharmaceutical dosage form according to the invention ispreferably for oral administration, preferably in form of a tablet.Further, according to this embodiment, a thrice daily administration canbe especially preferred since the preferred doses of the secondpharmacologically active ingredient may be as high as 2,500/n mg, thusrendering a tablet containing e.g. a maximum of 2,500/3 mg of the secondpharmacologically active ingredient much more patient compliant.

In still another preferred embodiment, the pharmaceutical dosage formaccording to the invention is for administration once daily (n=1),wherein the pharmaceutical dosage form contains the firstpharmacologically active ingredient in a dose of from 150/n to 1,200/nμg, preferably 200/n to 800/n μg, and the second pharmacologicallyactive ingredient in a dose of from 1.0/n to 2,500/n mg. According tothis embodiment, the pharmaceutical dosage form according to theinvention is preferably for oral administration, preferably in form of atablet.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention is for administration multiple daily (n=2, 3,4, 5 or 6), wherein the pharmaceutical dosage form contains the firstpharmacologically active ingredient in a dose of from 150/n to 1,200/nμg, preferably 200/n to 800/n μg, and the second pharmacologicallyactive ingredient in a dose of from 1.0/n to 2,500/n mg. According tothis embodiment, the pharmaceutical dosage form according to theinvention is preferably for oral administration, preferably in form of atablet. Further, according to this embodiment, a thrice dailyadministration can be especially preferred since the preferred doses ofthe second pharmacologically active ingredient may be as high as 2,500/nmg, thus rendering a tablet containing e.g. a maximum of 2,500/3 mg ofthe second pharmacologically active ingredient much more patientcompliant.

The pharmaceutical dosage form according to the invention may provideunder in vitro conditions immediate release or controlled release of thefirst pharmacologically active ingredient and/or the secondpharmacologically active ingredient. In vitro release is preferablydetermined in accordance with Ph. Eur., preferably paddle method withsinker, 75 rpm, 37° C., 900 mL artificial gastric juice, pH 6.8.

The first pharmacologically active ingredient and/or the secondpharmacologically active ingredient may independently of one another bepresent in the pharmaceutical dosage form at least partially incontrolled-release form. For example, the first pharmacologically activeingredient and/or the second pharmacologically active ingredient may bereleased from the pharmaceutical dosage form in a prolonged manner, e.g.if administered orally, rectally or percutaneously. Such pharmaceuticaldosage forms are particularly useful for “once-daily” or “twice-daily”preparations, which only have to be taken once a day, respectively,twice a day. Suitable controlled-release materials are well known tothose skilled in the art.

The pharmaceutical dosage form according to the invention providingcontrolled release of the first pharmacologically active ingredientand/or the second pharmacologically active ingredient may be producedusing materials, means, devices and processes that are well known in theprior art of pharmaceutical dosage forms.

In order to obtain a solid pharmaceutical dosage form such as a tablet,for example, the pharmacologically active ingredients of thepharmaceutical composition may be granulated with a pharmaceuticalcarrier, for example conventional tablet ingredients such as cornstarch, lactose, saccharose, sorbitol, talcum, magnesium stearate,dicalcium phosphate or pharmaceutically acceptable gums, andpharmaceutical diluents, for example water, in order to form a solidcomposition that contains the pharmacologically active ingredients inhomogeneous distribution. The term “homogeneous distribution” is takento mean that the pharmacologically active ingredients are distributeduniformly over the entire composition, so that said composition mayeasily be divided into equally effective dose units, such as tablets,pills or capsules and the like. The solid composition is then dividedinto dose units. The tablets or pills of the pharmaceutical compositionaccording to the invention may also be coated or compounded in adifferent manner, in order to provide a dosage form with a controlledrelease.

If one of the pharmacologically active ingredients is to be releasedprior to the other pharmacologically active ingredient, for example atleast 30 minutes or 1 hour beforehand, pharmaceutical dosage formshaving a corresponding release profile may be prepared. An example ofsuch a pharmaceutical dosage form is an osmotically-driven releasesystem for achieving a delayed release of either the first or the secondpharmacologically active ingredient from an inner part (core) of thepharmaceutical dosage form via a coating that itself contains the otherpharmacologically active ingredient which is accordingly releasedearlier. In a release system of this kind, which is particularlysuitable for oral administration, at least part, and preferably all, ofthe surface of the release system, preferably those parts that will comeinto contact with the release medium, is/are semipermeable, preferablyequipped with a semipermeable coating, so the surface(s) is/arepermeable to the release medium, but substantially, preferably entirely,impermeable to the pharmacologically active ingredient contained in thecore, the surface(s) and/or optionally the coating comprising at leastone opening for releasing the pharmacologically active ingredientcontained in the core. Moreover, precisely that/those surface(s) thatis/are in contact with the release medium is/are provided with a coatingcontaining and releasing the other pharmacologically active ingredient.This is preferably taken to mean a system in tablet form comprising arelease opening, a core containing the first or the secondpharmacologically active ingredient, a polymer portion that exertspressure upon swelling, a semipermeable membrane and a coatingcontaining the other pharmacologically active ingredient. Embodimentsand examples of osmotically-driven release systems are, for example,disclosed in U.S. Pat. Nos. 4,765,989, 4,783,337 and 4,612,008.

A further example of a suitable pharmaceutical dosage form is agel-matrix tablet. Suitable examples are provided in U.S. Pat. Nos.4,389,393, 5,330,761, 5,399,362, 5,472,711 and 5,455,046. Particularlysuitable is a retarding matrix dosage form, with an inhomogeneousdistribution of the pharmaceutical composition, whereby, for example,one pharmacologically active ingredient, i.e. the first or the secondpharmacologically active ingredient, is distributed in the outer region(the portion that comes into contact with the release medium mostquickly) of the matrix and the other pharmacologically active ingredientis distributed inside the matrix. On contact with the release medium,the outer matrix layer initially (and rapidly) swells and firstlyreleases the pharmacologically active ingredient contained therein,followed by the significantly (more) controlled release of the otherpharmacologically active ingredient. Examples of a suitable matrixinclude matrices with 1 to 80% by weight of one or more hydrophilic orhydrophobic polymers as pharmaceutically acceptable matrix formers.

Preferably, the pharmaceutical dosage form according to the inventionprovides immediate release of the first pharmacologically activeingredient, and immediate or controlled release of the secondpharmacologically active ingredient.

In a preferred embodiment, the pharmaceutical dosage form according tothe invention provides immediate release of both, the first and thesecond pharmacologically active ingredient. In this particular case, amultiple daily administration, in particular an administration twicedaily, thrice daily, or up to six times a day is preferred.

In another preferred embodiment, the pharmaceutical dosage formaccording to the invention provides immediate release of the firstpharmacologically active ingredient, and controlled release of thesecond pharmacologically active ingredient. This release profile may berealized by employing the aforementioned methods, e.g. theosmotically-driven release system providing the first pharmacologicallyactive ingredient in the coating and the second pharmacologically activeingredient in the core, or the retarding matrix dosage form containingthe first pharmacologically active ingredient in the outer matrix layerand the second pharmacologically active ingredient in the inside of thematrix.

In yet another preferred embodiment, the pharmaceutical dosage formaccording to the invention provides controlled release of both the firstand the second pharmacologically active ingredient.

In a further aspect, the invention relates to the use of thepharmaceutical composition according to the invention, and thepharmaceutical dosage form according to the invention respectively, inthe prevention or treatment of pain, anxiety or epilepsy.

In a preferred embodiment, the pharmaceutical composition according tothe invention and the pharmaceutical dosage form according to theinvention, respectively, are for use in the treatment of pain, whereinthe pain is preferably

-   -   peripheral, central or muscle skeletal pain; and/or    -   acute, subacute or chronic pain; and/or    -   moderate to severe pain; and/or    -   neuropathic or psychogenic or nociceptive or mixed pain; and/or    -   low back pain, visceral pain or headache; and/or    -   post-operative (post-surgical), cancer or inflammatory pain.

For the purpose of specification, “acute pain” preferably refers to painthat lasts up to about 4 weeks, “subacute pain” preferably refers topain that lasts from more than about 4 weeks to about 12 weeks, and“chronic pain” preferably refers to pain that lasts for more than about12 weeks.

Preferably, the pain is selected from the group consisting of cancerpain, peripheral neuropathic pain, osteoarthritis, chronic visceralpain, neuropathic pain (diabetic polyneuropathy, HIV-associatedneuropathic pain, posttraumatic neuropathic pain, postherpeticneuralgia, chemotherapy associated pain), postzosteric neuralgia,postoperative neuropathic pain, inflammatory pain, migraine, low-backpain, fibromyalgia and trigeminal neuralgia.

In the following, the doses of the first and the secondpharmacologically active ingredient are again expressed according to thenumber of administrations “n” per day, i.e. the number ofadministrations of the pharmaceutical dosage form according to theinvention in the course of 24 hours.

In a preferred embodiment, the pharmaceutical dosage form is for use inthe treatment of neuropathic pain, which may optionally superimposed bynociceptive pain, where the dose of the first pharmacologically activeingredient contained in the pharmaceutical dosage form preferably is inthe range of 1/n μg to 800/n μg or 1/n μg to 600/n μg or 1/n μg to 400/nμg or 1/n μg to 250/n μg, more preferably in the range of 5/n μg to150/n μg, even more preferably in the range of 10/n μg to 100/n μg, mostpreferably in the range of 20/n μg to 80/n μg and in particular mostpreferably in the range of 30/n μg to 50/n μg. According to thisembodiment, the dose of the second pharmacologically active ingredientcontained in the pharmaceutical dosage form preferably is in the rangeof 1.0/n mg to 2,500/n mg.

In a preferred embodiment, in particular when the pharmaceutical dosageform is for use in the treatment of neuropathic pain and the secondpharmacologically active ingredient is retigabin or a physiologicallyacceptable salt thereof, the dose of the first pharmacologically activeingredient contained in the pharmaceutical dosage form preferably is inthe range of 1/n μg to 800/n μg or 1/n μg to 600/n μg or 1/n μg to 400/nμg or 1/n μg to 250/n μg, more preferably in the range of 5/n μg to150/n μg, even more preferably in the range of 10/n μg to 100/n μg, mostpreferably in the range of 20/n μg to 80/n μg and in particular mostpreferably in the range of 30/n μg to 50/n μg; and the dose of thesecond pharmacologically active ingredient contained in thepharmaceutical dosage form preferably is in the range of 200/n mg to1,800/n mg or 1,500/n mg, more preferably in the range of 300/n mg to1,400/n mg, even more preferably in the range of 400/n mg to 1,300/n mg,most preferably in the range of 500/n mg to 1,200/n mg and in particularin the range of 600/n mg to 1,000/n mg.

In another preferred embodiment, in particular when the pharmaceuticaldosage form is for use in the treatment of neuropathic pain and thesecond pharmacologically active ingredient contained in thepharmaceutical dosage form is a benzodiazepine derivative, the dose ofthe first pharmacologically active ingredient preferably is in the rangeof 1/n μg to 800/n μg or 1/n μg to 600/n μg or 1/n μg to 400/n μg or 1/nμg to 250/n μg, more preferably in the range of 5/n μg to 150/n μg, evenmore preferably in the range of 10/n μg to 100/n μg, most preferably inthe range of 20/n μg to 80/n μg and in particular most preferably in therange of 30/n μg to 50/n μg; and the dose of the secondpharmacologically active ingredient contained in the pharmaceuticaldosage form preferably is in the range of 0.005/n mg to 400/n mg or300/n mg, more preferably in the range of 0.01/n mg to 200/n mg, stillmore preferably in the range of 0.05/n mg to 150/n mg, yet morepreferably in the range of 0.1/n mg to 100/n mg, even more preferably inthe range of 0.5/n mg to 80/n mg, most preferably in the range of 0.75/nmg to 60/n mg and in particular in the range of 1.0/n mg to 40/n mg.

In another preferred embodiment, the pharmaceutical dosage form is foruse in the treatment of nociceptive pain which may optionallysuperimposed by nociceptive pain, where the dose of the firstpharmacologically active ingredient contained in the pharmaceuticaldosage form preferably is in the range of 50/n μg to 2,000/n μg or 50/nμg to 1,400/n μg or 50/n μg to 1,200/n μg or 50/n μg to 1,000/n μg, morepreferably in the range of 100/n μg to 800/n μg, still more preferablyin the range of 150/n μg to 650/n μg, even more preferably in the rangeof 250/n μg to 550/n μg, and most preferably in the range of 350/n μg to450/n μg. According to this embodiment, the dose of the secondpharmacologically active ingredient contained in the pharmaceuticaldosage form preferably is in the range of 1.0/n mg to 2,500/n mg.

In a preferred embodiment, in particular when the pharmaceutical dosageform is for use in the treatment of nociceptive pain and the secondpharmacologically active ingredient is retigabin or a physiologicallyacceptable salt thereof, the dose of the first pharmacologically activeingredient contained in the pharmaceutical dosage form preferably is inthe range of 50/n μg to 2,000/n μg or 50/n μg to 1,400/n μg or 50/n μgto 1,200/n μg or 50/n μg to 1,000/n μg, more preferably in the range of100/n μg to 800/n μg, still more preferably in the range of 150/n μg to650/n μg, even more preferably in the range of 250/n μg to 550/n μg, andmost preferably in the range of 350/n μg to 450/n μg; and the dose ofthe second pharmacologically active ingredient contained in thepharmaceutical dosage form preferably is in the range of 200/n mg to1,800/n mg or 1,500/n mg, more preferably in the range of 300/n mg to1,400/n mg, even more preferably in the range of 400/n mg to 1,300/n mg,most preferably in the range of 500/n mg to 1,200/n mg and in particularin the range of 600/n mg to 1,000/n mg.

In another preferred embodiment, in particular when the pharmaceuticaldosage form is for use in the treatment of nociceptive pain and thesecond pharmacologically active ingredient is benzodiazepine derivative,the dose of the first pharmacologically active ingredient contained inthe pharmaceutical dosage form preferably is in the range of 50/n μg to2,000/n μg or 50/n μg to 1,400/n μg or 50/n μg to 1,200/n μg or 50/n μgto 1,000/n μg, more preferably in the range of 100/n μg to 800/n μg,still more preferably in the range of 150/n μg to 650/n μg, even morepreferably in the range of 250/n μg to 550/n μg, and most preferably inthe range of 350/n μg to 450/n μg; and the dose of the secondpharmacologically active ingredient contained in the pharmaceuticaldosage form preferably is in the range of 0.005/n mg to 400/n mg or300/n mg, more preferably in the range of 0.01/n mg to 200/n mg, stillmore preferably in the range of 0.05/n mg to 150/n mg, yet morepreferably in the range of 0.1/n mg to 100/n mg, even more preferably inthe range of 0.5/n mg to 80/n mg, most preferably in the range of 0.75/nmg to 60/n mg and in particular in the range of 1.0/n mg to 40/n mg.

Preferably, the pharmaceutical composition contains the first and thesecond pharmacologically active ingredient in such a weight ratio thatthey will exert a synergistic therapeutic effect upon administration toa patient. Thereby, the term “synergistic therapeutic effect” may referto a synergistic therapeutic effect with respect to the prevention ortreatment of pain (synergistic analgesic effect), a synergistictherapeutic effect with respect to the prevention or treatment ofanxiety (synergistic anxiolytic effect) as well as a synergistictherapeutic effect with respect to the prevention or treatment ofepilepsy (synergistic anti-convulsive effect). Suitable weight ratios ofthe pharmacologically active ingredients generating the synergistictherapeutic effect can be determined by methods well known to thoseskilled in the art.

A further aspect of the invention relates to a method of treating orpreventing pain, anxiety or epilepsy comprising the preferably twicedaily or once daily, preferably oral administration of thepharmaceutical dosage form according to the invention to a subject inneed thereof.

In a preferred embodiment, the invention relates to a combination of(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof with retigabin or aphysiologically acceptable salt thereof. All preferred embodiments ofthe invention that have been described and defined above also apply tothis specific combination and thus, are not reiterated hereinafter.

In a preferred embodiment, the invention relates to a combination of(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof with lamotrigine or aphysiologically acceptable salt thereof. All preferred embodiments ofthe invention that have been described and defined above also apply tothis specific combination and thus, are not reiterated hereinafter.

In a preferred embodiment, the invention relates to a combination of(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof with lacosamide or aphysiologically acceptable salt thereof. All preferred embodiments ofthe invention that have been described and defined above also apply tothis specific combination and thus, are not reiterated hereinafter.

In a preferred embodiment, the invention relates to a combination of(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof with levetiracetam or aphysiologically acceptable salt thereof. All preferred embodiments ofthe invention that have been described and defined also above apply tothis specific combination and thus, are not reiterated hereinafter.

In a preferred embodiment, the invention relates to a combination of(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof with carbamazepine or aphysiologically acceptable salt thereof. All preferred embodiments ofthe invention that have been described and defined above also apply tothis specific combination and thus, are not reiterated hereinafter.

In a particular preferred embodiment,

-   -   the first pharmacologically active ingredient is        (1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amine        according to formula (I) in form of its free base, or a        hemicitrate, hydrochloride or maleate salt thereof; and/or    -   the second pharmacologically active ingredient is retigabine,        carbamazepine, lamotrigine, levetriacetam, lacosamide, or a        physiologically acceptable salt thereof, in particular a        hydrochloride salt; and/or    -   the pharmaceutical composition and the pharmaceutical dosage        form, respectively, contain the first pharmacologically active        ingredient in a dose of from 20 μg to 80 μg or of from 80 μg to        200 μg or of from 200 μg to 800 μg or of from 800 μg to 1,200        μg; and/or    -   the pharmaceutical composition and the pharmaceutical dosage        form, respectively, contain the second pharmacologically active        ingredient in a dose of from 1.0 mg to 3,000 mg, and/or    -   the relative weight ratio of the first pharmacologically active        ingredient to the second pharmacologically active ingredient is        within the range of from 1:2 to 1:100,000,000, preferably 1:5 to        1:100,000 in the pharmaceutical composition and the        pharmaceutical dosage form, respectively; and/or    -   the pharmaceutical composition is for use in the prevention or        treatment of pain, anxiety or epilepsy; and/or    -   the pharmaceutical composition is for use in the treatment of        pain, wherein the pain is peripheral, central or muscle skeletal        pain; and/or acute, subacute or chronic pain; and/or moderate to        severe pain; and/or neuropathic or psychogenic or nociceptive or        mixed pain; and/or low back pain, visceral pain or headache;        and/or post-operative (post-surgical), cancer or inflammatory        pain; and/or    -   the pharmaceutical composition and the pharmaceutical dosage        form, respectively, contain the first pharmacologically active        ingredient and the second pharmacologically active ingredient in        such a weight ratio that upon administration to a patient they        will exert a synergistic therapeutic effect; and/or    -   the pharmaceutical dosage form provides immediate release of the        first pharmacologically active ingredient in vitro in accordance        with Ph. Eur.; and/or    -   the pharmaceutical dosage form provides immediate or controlled        release of the second pharmacologically active ingredient in        vitro in accordance with Ph. Eur.; and/or    -   the pharmaceutical dosage form is for oral administration;        and/or    -   the pharmaceutical dosage form is for administration once, twice        or thrice daily.

In a further aspect, the invention relates to a kit comprising a firstpharmaceutical dosage form comprising the first pharmacologically activeingredient as described above, and a second pharmaceutical dosage formcomprising the second pharmacologically active ingredient as describedabove.

A suitable embodiment is a kit in which the first pharmaceutical dosagefrom comprising the first pharmacologically active ingredient and thesecond pharmaceutical dosage form comprising the secondpharmacologically active ingredient, although spatially separated, areprovided in a common presentation form, e.g. packaging.

Preferably, the first and the second pharmaceutical dosage form areadapted for simultaneous or sequential administration, wherein the firstpharmaceutical dosage form may be administered before or after thesecond pharmaceutical dosage form and wherein the first and the secondpharmaceutical dosage form are administered either via the same or adifferent pathway of administration.

For the purpose of specification, the term “simultaneous administration”preferably refers to an administration of the first and the secondpharmaceutical dosage form within a time span of 15 minutes from eachother, whereas the term “sequential administration” preferably refers toan administration of the first and the second pharmaceutical dosage formwithin a time span of more than 15 minutes from each other.

In a preferred embodiment, the first and the second pharmaceuticaldosage form are adapted for administration to the patient via the samepathway.

In another preferred embodiment, the first and the second pharmaceuticaldosage form are adapted for administration to the patient via differentpathways.

In a preferred embodiment, the first and the second pharmaceuticaldosage form are administered simultaneously.

In another preferred embodiment, the first and the second pharmaceuticaldosage form are administered sequentially.

In a preferred embodiment, the first and/or the second pharmaceuticaldosage form are adapted for once daily administration.

In another preferred embodiment, the first and/or the secondpharmaceutical dosage form are adapted for multiple dailyadministration, in particular twice daily or thrice daily.

In a preferred embodiment, the first pharmaceutical dosage form isadapted for once daily administration and the second pharmaceuticaldosage form is adapted for multiple daily, in particular twice daily orthrice daily, administration.

Suitable pathways of administration of the pharmaceutical dosage formscontained in the kit include but are not limited to oral, intravenous,intraperitoneal, intradermal, intrathecal, intramuscular, intranasal,transmucosal, subcutaneous, and/or rectal administration.

In a preferred embodiment, one or both of the pharmaceutical dosageforms contained in the kit are for oral administration.

In another preferred embodiment, one or both of the pharmaceuticaldosage forms contained in the kit are for parenteral administration, inparticular intravenous, intraperitoneal, intrathecal, intramuscular, orsubcutaneous administration.

In a preferred embodiment, the first and the second pharmaceuticaldosage form are for oral, simultaneous administration once daily.

In another preferred embodiment, the first and the second pharmaceuticaldosage form are for oral, simultaneous administration multiple daily, inparticular twice daily or thrice daily.

In still another preferred embodiment, the first and the secondpharmaceutical dosage form are each for oral, sequential administrationonce daily.

In a preferred embodiment, the first and the second pharmaceuticaldosage form are for sequential administration once daily each, where thefirst and the second pharmaceutical dosage form are adapted foradministration via different pathways, e.g. oral and parenteraladministration.

In another preferred embodiment, the first and the second pharmaceuticaldosage form are each for oral, sequential administration multiple daily,in particular twice daily or thrice daily.

In another preferred embodiment, the first and the second pharmaceuticaldosage form are for sequential administration multiple daily each, inparticular twice daily or thrice daily, where the first and the secondpharmaceutical dosage form are adapted for administration via differentpathways, e.g. oral and parenteral administration.

The following examples further illustrate the invention but are not tobe construed as limiting its scope.

Pharmacological Methods: In Vivo Experiments According to Chung

In the following, all amounts of the first pharmacologically activeingredient are specified as the hemicitrate salt.

The weight ratios of the first and the second pharmacologically activeingredient that will lead to a supra-additive effect/synergistic effectmay be determined in the test of Kim & Chung (Kim S H, Chung J M. Anexperimental model for peripheral mononeuropathy produced by segmentalspinal nerve ligation in the rat. Pain 1992; 50: 355-63) as described inSchroder et al., Eur. J. Pain 2010, 14: 814. Said references are herebyincorporated by reference and form part of the disclosure.

Ligatures were applied to the left L5/L6 spinal nerves of maleSprague-Dawley rats (140-160 g body weight, Janvier, Genest St. Isle,France). Animals developed tactile allodynia at the ipsilateral paw. Oneto four weeks after the operation the tactile allodynia thresholdbaseline (withdrawal threshold) was measured on the ipsilateral andcontralateral hind paw by an electronic von Frey anaesthesiometer(Somedic, Schweden). After test and measurement of the baseline, thefirst pharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the hemicitrate salt, and the second pharmacologically activeingredient in form of retigabine dihydrochloride according to theinvention were each dissolved in a mixture of DMSO (10%), Cremophor (5%)and glucose solution (85%) and injected by the intravenous (i.v.) route(application volume 5 ml/kg). The first and the second pharmacologicallyactive ingredient were either administered as the respective singlesubstance or both at the same time. Animals were randomly assigned togroups of 10 for each test dose and vehicle (DMSO (10%), Cremophor (5%)and glucose solution (85%)) and tactile withdrawal thresholds weretested 0.5 h before administration and on several time points (0.5, 1and 3 hours) after intravenous administration. Ipsi- and contralateralhindpaws were tested. The median of the withdrawal threshold for eachanimal at a given time is calculated from five individual stimulationswith the electronic von Frey filament. Withdrawal thresholds of theinjured paws are expressed as % MPE (Maximum possible effect) comparingpredrug threshold of Chung-Animals (=0% MPE) and control threshold ofsham-animals (100% MPE). A cut-off is set at 100% MPE. The effect ofeach compound and vehicle is calculated for each testing time point asinterindividual % MPE value.

Data (anti-allodynic efficacy (% MPE), ipsi-lateral, paw withdrawalthreshold, ipsi- and conralateral) were analyzed by means of atwo-factor analysis of variance (ANOVA) with repeated measures. In caseof a significant treatment effect, post hoc analysis with Bonferroniadjustment was performed. Results were considered statisticallysignificant if p<0.05.

In Vivo Experiments According to Randall Selitto Test in Rats

The weight ratios of the first and the second pharmacologically activeingredient that will lead to a supra-additive effect (synergisticeffect) may be determined via the test of Randall and Selitto asdescribed in Arch. Int. Pharmacodyn., 1957, 111: 409-419, which is amodel for inflammatory pain. The respective part of the literature ishereby incorporated by reference and forms part of the presentdisclosure.

By means of injection of 0.1 ml of carrageenan-suspension ventrally intoa hind paw of a rat an oedema is induced, on which pain is generated 4hours later by continuously increasing pressure with a stamp (2 mm tipdiameter). The antinociceptive and antihyperalgesic activity of thetested pharmacologically active ingredient is determined at differentpoints in time after administration of the pharmacologically activeingredient. The measured value to be determined and at the same timealso the end point of the pain test is the pressure at which thevocalization reaction of the rat occurs. The percentage maximum possibleeffect (% MPE) is calculated. The maximum pressure of the stamp is 250g. The group size is n=12.

ED₅₀ values were determined by regression analysis in case ofdose-dependent results (according to Litchfield J. T. and Wilcoxon F.A., A simplified method of evaluating dose-effect experiments, J.Pharmacol. Exp. Ther. 1949; 96: 99-113). The analysis of the resultswith respect to a supra-additive effect of the first and the secondpharmacologically active ingredient is carried out via statisticalcomparison of the theoretical additive ED₅₀-value with theexperimentally determined ED₅₀-value of a so-called fixed ratiocombination (isobolographic analysis according to Tallarida J. T.,Porreca F., and Cowan A., Statistical analysis of drug-drug andsite-site interactions with isobolograms, Life Sci. 1989; 45: 947-961).

The interactions studies presented herein were performed usingequieffective doses of the first and the second pharmacologically activeingredient, calculated from the ratio of the respective ED₅₀ values ofthe first and the second pharmacologically active ingredient ifadministered alone.

The application route was intravenous (i.v.) for the firstpharmacologically active ingredient and intraperitoneal (i.p.) for thesecond pharmacologically active ingredient. The first pharmacologicallyactive ingredient was dissolved in 5% DMSO, 5% Cremophor and 90% glucosesolution (5%). The second pharmacologically active ingredient wasdissolved in 1% CMC in aqua dest. Intraveneous (i.v.) andintraperitoneal (i.p.) applications were made in a volume of 5 ml/kg.

In case of the combined, simultaneous administration, the relative doseratio of first pharmacologically active ingredient to the secondpharmacologically active ingredient was calculated from the ratio of therespective ED50 ratios.

Results: Chung Experiment: EXAMPLE 1 First Pharmacologically ActiveIngredient in Combination with Retigabine

The first pharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the hemicitrate salt (0.0316 μg/kg body weight i.v.) showed awithdrawal threshold of the ipsi-lateral hind paw with an efficacy of20.7% MPE at 30 min. after administration.

The second pharmacologically active ingredient retigabinedihydrochloride (1.0 mg/kg body weight i.v.) showed a withdrawalthreshold of the ipsi-lateral hind paw with an efficacy of 23.1% MPE at30 min. after administration.

When administered as a combination, the first and the secondpharmacologically active ingredient were tested in a fixed ratio of3.16:100,000 (first to second pharmacologically active ingredient) indoses of 0.0316 μg/kg body weight+1.0 mg/kg body weight i.v. of thefirst and the second pharmacologically active ingredient, respectively.This combined administration of the first and the secondpharmacologically active ingredient resulted in a supra-additiveincrease in the withdrawal threshold of the ipsi-lateral hind pawcompared to the administration of the single pharmacologically activeingredients showing a synergistic effect with 53.6% MPE at 30 min afteradministration.

FIG. 1 shows % MPE in dependence of the time elapsed afteradministration.

Legend of FIG. 1:

-    vehicle (n=10)-   ▴ first pharmacologically active ingredient (0.0316 μg/kg, n=10)-   ▾ second pharmacologically active ingredient (1.0 mg/kg, n=10)-   combination of first and second pharmacologically active ingredient    (0.0316 μg/kg+1.0 mg/kg, n=10)-   - - - theoretical additive value

Experimental results demonstrating supra-additive effect of thecombination of the first and the second pharmacologically activeingredient are summarized in the following table 1.

TABLE 1 % MPE (Maximum possible effect) of the first and the secondpharmacologically active ingredient and the combination of the first andthe second pharmacologically active ingredient: % MPE 30 min. 60 min.180 min. (n = 10) (n = 10) (n = 10) Dose Mean SEM Mean SEM Mean SEMVehicle −1.4 ± 3.5  −5.7 ± 6.0   2.9 ± 5.0 first pharmacologically 20.7± 12.4  8.2 ± 10.6 −1.3 ± 6.0 active ingredient second pharmacologically23.1 ± 5.0  −2.0 ± 7.9  −2.8 ± 8.0 active ingredient first + second 53.6± 12.9 5.5 ± 9.2 10.4 ± 9.6 pharmacologically active ingredient

The experimental % MPE value of 53.6 (30 min.) in case of the combinedadministration of the first and the second pharmacologically activeingredient according to the invention is above the theoretical additive% MPE value of the single pharmacologically active ingredients. Thus,the interaction of the first and the second pharmacologically activeingredient is synergistic.

The results of the statistical analysis of the experimental data aresummarized in table 2.

TABLE 2 Statistical evaluation of the data following two-factor analysisof variance (ANOVA) and post hoc analysis with Bonferroni adjustment.Statistical evaluation: % MPE treatment time interaction repeatedF(3,36) = 2.381 F(2,72) = 15.410 F(6,72) = 3.205 measures p = 0.086 p =0.000 p = 0.008 ANOVA post hoc analysis Bonferroni adjustment 30 min. 60min. 180 min. vehicle + vehicle + second p = 0.450 p = 1.000 p = 1.000vehicle vs. pharmacologically active ingredient first pharmacologicallyp = 0.633 p = 1.000 p = 1.000 active ingredient + vehicle first + secondp = 0.001 p = 1.000 p = 1.000 pharmacologically active ingredient p:Level of statistical significance.

As can be seen from table 2, the experimental results are statisticallysignificant (p<0.05). The synergistic effect of the first and the secondpharmacologically active ingredient according to the invention isverified by the Bonferroni adjustment giving values of p<0.05.

Thus, synergistic effect of the first and the second pharmacologicallyactive ingredient results in increased anti-nociceptive effects.

Randall Selitto Experiments: EXAMPLE 2 First Pharmacologically ActiveIngredient in Combination with Carbamazepine

The application route was intravenous (i.v.) for the firstpharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano-[3,4,b]indol]-4-aminein form of the hemicitrate salt and intraperitoneal (i.p.) for thesecond pharmacologically active ingredient carbamazepine. The firstpharmacologically active ingredient was dissolved in 5% DMSO, 5%Cremophor and 90% glucose solution (5%). The second pharmacologicallyactive ingredient was dissolved in 1% CMC in aqua dest. Intraveneous(i.v.) and intraperitoneal (i.p.) applications were made in a volume of5 ml/kg.

In case of the combined, simultaneous administration, the relative doseratio of first pharmacologically active ingredient to the secondpharmacologically active ingredient was 1:9053.

When the first pharmacologically active ingredient was applied alone,the peak effect was reached 15 min p. appl. (timepoint of firstmeasurement) corresponding to an ED₅₀-value of 3.48 (3.07-3.89) μg/kgi.v. The second pharmacologically active ingredient induced adose-dependent analgesic effect with ED₅₀-values of 29971 (28660-31466)μg/kg i.p., reaching the peak effect 15 min p. appl. According to theirrespective timepoint of peak effect, the first pharmacologically activeingredient was applied simultaneously with the second pharmacologicallyactive ingredient 15 min before timepoint of measurement of theinteraction-experiments.

Thus, the time point of ED₅₀ calculation in case of the combinedadministration of the first and the second pharmacologically activeingredient according to the invention corresponds to the timepoint ofthe peak effect of the respective pharmacologically active ingredient.The isobolographic analysis revealed that the experimental ED₅₀-valuesregarding the combined administration of the first and the secondpharmacologically active ingredient were significantly lower than therespective theoretical ED₅₀-values. Thus, the combination studiesdemonstrate significant synergistic interaction of the firstpharmacologically active ingredient with the second pharmacologicallyactive ingredient.

FIG. 2 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and carbamazepine as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

ED₅₀ (95% CI) [μg/kg] (i.v./i.p.) first pharmacologically activeingredient = 3.48 (3.07-3.89) second pharmacologically active ingredient= 29971 (28660-31466) theoretical additive value = 15361 (14425-16291)part of first pharmacologically active 1.70 (1.59-1.80) ingredient =part of second pharmacologically active 15360 (14424-16295) ingredient =experimental value of the combined 10404 (9828-10971) administration ofthe first and the second pharmacologically active ingredient = part offirst pharmacologically active 1.15 (1.02-1.28) ingredient = part ofsecond pharmacologically active 10403 (9915-10891) ingredient =

The results of the isobolographic analysis are summarized in thefollowing table 3.

TABLE 3 Experimental ED₅₀ values of the first and the secondpharmacologically active ingredient and isobolographic analysis of theinteraction between the first and the second pharmacologically activeingredient: Substance/ED₅₀ [μg/kg] (confidence interval) TheoreticalED₅₀ Experimental first second [μg/kg] of the ED₅₀ [μg/kg] ofpharmacologically pharmacologically combined the combined activeingredient active ingredient administration administration Interaction3.48 (3.07-3.89) 29971 (28660-31466) 15361 (14425-16291) 10404(9828-10971) supra- additive (p < 0.001) p: level of statisticalsignificance.

As can be seen from table 3, the experimental results are statisticallysignificant (p<0.05). Thus, synergistic effect of the first and thesecond pharmacologically active ingredient results in increasedanti-nociceptive effects.

EXAMPLE 3 First Pharmacologically Active Ingredient in Combination withLamotrigine

The application route was intravenous (i.v.) for the firstpharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano-[3,4,b]indol]-4-aminein form of the hemicitrate salt and intraperitoneal (i.p.) for thesecond pharmacologically active ingredient lamotrigine. The firstpharmacologically active ingredient was dissolved in 5% DMSO, 5%Cremophor and 90% glucose solution (5%). The second pharmacologicallyactive ingredient was dissolved in 1% CMC in aqua dest. Intraveneous(i.v.) and intraperitoneal (i.p.) applications were made in a volume of5 ml/kg.

In case of the combined, simultaneous administration, the relative doseratio of first pharmacologically active ingredient to the secondpharmacologically active ingredient was 1:10649.

When the first pharmacologically active ingredient was applied alone,the peak effect was reached 15 min p. appl. (timepoint of firstmeasurement) corresponding to an ED₅₀-value of 3.48 (3.07-3.89) μg/kgi.v. The second pharmacologically active ingredient induced adose-dependent analgesic effect with ED₅₀-values of 29971 (28660-31466)μg/kg i.p., reaching the peak effect 15 min p. appl. According to theirrespective timepoint of peak effect, the first pharmacologically activeingredient was applied simultaneously with the second pharmacologicallyactive ingredient 15 min before timepoint of measurement of theinteraction-experiments.

Thus, the time point of ED₅₀ calculation in case of the combinedadministration of the first and the second pharmacologically activeingredient according to the invention corresponds to the timepoint ofthe peak effect of the respective pharmacologically active ingredient.The isobolographic analysis revealed that the experimental ED₅₀-valuesregarding the combined administration of the first and the secondpharmacologically active ingredient were significantly lower than therespective theoretical ED₅₀-values. Thus, the combination studiesdemonstrate significant synergistic interaction of the firstpharmacologically active ingredient with the second pharmacologicallyactive ingredient.

FIG. 3 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and carbamazepine as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

ED₅₀ (95% CI) [μg/kg] (i.v./i.p.) first pharmacologically activeingredient = 3.48 (3.07-3.89) second pharmacologically active ingredient= 35253 (38082-32740) theoretical additive value = 18068 (16840-19296)part of first pharmacologically active 1.70 (1.58-1.81) ingredient =part of second pharmacologically active 18066 (16838-19295) ingredient =experimental value of the combined 9982 (9043-10856) administration ofthe first and the second pharmacologically active ingredient = part offirst pharmacologically active 0.937 (0.828-1.05) ingredient = part ofsecond pharmacologically active 9981 (9924-10739) ingredient =

The results of the isobolographic analysis are summarized in thefollowing table 4.

TABLE 4 Experimental ED₅₀ values of the first and the secondpharmacologically active ingredient and isobolographic analysis of theinteraction between the first and the second pharmacologically activeingredient: Substance/ED₅₀ [μg/kg] (confidence interval) TheoreticalED₅₀ Experimental first second [μg/kg] of the ED₅₀ [μg/kg] ofpharmacologically pharmacologically combined the combined activeingredient active ingredient administration administration Interaction3.48 (3.07-3.89) 35253 (38082-32740) 18068 (16840-19296) 9982(9043-10856) supra- additive (p < 0.001) p: level of statisticalsignificance.

As can be seen from table 4, the experimental results are statisticallysignificant (p<0.05). Thus, synergistic effect of the first and thesecond pharmacologically active ingredient results in increasedanti-nociceptive effects.

EXAMPLE 4 First Pharmacologically Active Ingredient in Combination withLevetiracetam

The application route was intravenous (i.v.) for the firstpharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano-[3,4,b]indol]-4-aminein form of the hemicitrate salt and intraperitoneal (i.p.) for thesecond pharmacologically active ingredient levetiracetam. The firstpharmacologically active ingredient was dissolved in 5% DMSO, 5%Cremophor and 90% glucose solution (5%). The second pharmacologicallyactive ingredient was dissolved in 1% CMC in aqua dest. Intraveneous(i.v.) and intraperitoneal (i.p.) applications were made in a volume of5 ml/kg.

In case of the combined, simultaneous administration, the relative doseratio of first pharmacologically active ingredient to the secondpharmacologically active ingredient was 1:297817.

When the first pharmacologically active ingredient was applied alone,the peak effect was reached 15 min p. appl. (timepoint of firstmeasurement) corresponding to an ED₅₀-value of 3.48 (3.07-3.89) μg/kgi.v. The second pharmacologically active ingredient Levetiracetaminduced a dose-dependent analgesic effect with ED₅₀-values of 985957(853986-1137284) μg/kg i.p., reaching the peak effect 15 min p. appl.According to their respective timepoint of peak effect, the firstpharmacologically active ingredient was applied simultaneously with thesecond pharmacologically active ingredient 15 min before timepoint ofmeasurement of the interaction-experiments.

Thus, the time point of ED₅₀ calculation in case of the combinedadministration of the first and the second pharmacologically activeingredient according to the invention corresponds to the timepoint ofthe peak effect of the respective pharmacologically active ingredient.The isobolographic analysis revealed that the experimental ED₅₀-valuesregarding the combined administration of the first and the secondpharmacologically active ingredient were significantly lower than therespective theoretical ED₅₀-values. Thus, the combination studiesdemonstrate significant synergistic interaction of the firstpharmacologically active ingredient with the second pharmacologicallyactive ingredient.

FIG. 4 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and levetiracetam as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

ED₅₀ (95% CI) [μg/kg] (i.v./i.p.) first pharmacologically activeingredient = 3.48 (3.07-3.89) second pharmacologically active 985957(853986-1137284) ingredient = heoretical additive value = 505277(459009-551546) part of first pharmacologically 1.70 (1.54-1.85) activeingredient = art of second pharmacologically 505276 (459008-551544)active ingredient = xperimental value of the combined 274945(256029-292241) administration of the first and the secondpharmacologically active ingredient = part of first pharmacologicallyactive 0.923 (0.816-1.031) ingredient = art of second pharmacologicallyactive 274944 (235349-314538) ingredient =

The results of the isobolographic analysis are summarized in thefollowing table 5.

TABLE 5 Experimental ED₅₀ values of the first and the secondpharmacologically active ingredient and isobolographic analysis of theinteraction between the first and the second pharmacologically activeingredient: Substance/ED₅₀ [μg/kg] (confidence interval) TheoreticalED₅₀ Experimental first second [μg/kg] of the ED₅₀ [μg/kg] ofpharmacologically pharmacologically combined the combined activeingredient active ingredient administration administration Interaction3.48 (3.07-3.89) 985957 (853986-1137284) 505277 (459009-551546) 274945(256029-292241) supra- additive (p < 0.001) p: level of statisticalsignificance.

As can be seen from table 5, the experimental results are statisticallysignificant (p<0.05). Thus, synergistic effect of the first and thesecond pharmacologically active ingredient results in increasedanti-nociceptive effects.

EXAMPLE 5 First Pharmacologically Active Ingredient in Combination withLacosamide

The application route was intravenous (i.v.) for the firstpharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano-[3,4,b]indol]-4-aminein form of the hemicitrate salt and intraperitoneal (i.p.) for thesecond pharmacologically active ingredient lacosamide. The firstpharmacologically active ingredient was dissolved in 5% DMSO, 5%Cremophor and 90% glucose solution (5%). The second pharmacologicallyactive ingredient was dissolved in 1% CMC in aqua dest. Intraveneous(i.v.) and intraperitoneal (i.p.) applications were made in a volume of5 ml/kg.

In case of the combined, simultaneous administration, the relative doseratio of first pharmacologically active ingredient to the secondpharmacologically active ingredient was 1:10653.

When the first pharmacologically active ingredient was applied alone,the peak effect was reached 15 min p. appl. (timepoint of firstmeasurement) corresponding to an ED₅₀-value of 3.48 (3.07-3.89) μg/kgi.v. The second pharmacologically active ingredient induced adose-dependent analgesic effect with ED₅₀-values of 35267 (34433-36022)μg/kg i.p., reaching the peak effect 15 min p. appl. According to theirrespective timepoint of peak effect, the first pharmacologically activeingredient was applied simultaneously with the second pharmacologicallyactive ingredient 15 min before timepoint of measurement of theinteraction-experiments.

Thus, the time point of ED₅₀ calculation in case of the combinedadministration of the first and the second pharmacologically activeingredient according to the invention corresponds to the timepoint ofthe peak effect of the respective pharmacologically active ingredient.The isobolographic analysis revealed that the experimental ED₅₀-valuesregarding the combined administration of the first and the secondpharmacologically active ingredient were significantly lower than therespective theoretical ED₅₀-values. Thus, the combination studiesdemonstrate significant synergistic interaction of the firstpharmacologically active ingredient with the second pharmacologicallyactive ingredient.

FIG. 5 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and lacosamide as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

ED₅₀ (95% CI) [μg/kg] (i.v./i.p.) first pharmacologically activeingredient = 3.48 (3.07-3.89) second pharmacologically active ingredient= 35267 (34433-36022) theoretical additive value = 18075 (17040-19110)part of first pharmacologically active 1.70 (1.60-1.79) ingredient =part of second pharmacologically active 18074 (17039-19109) ingredient =experimental value of the combined 9649 (9106-10137) administration ofthe first and the second pharmacologically active ingredient = part offirst pharmacologically active 0.906 (0.800-1.01) ingredient = part ofsecond pharmacologically active 9649 (9431-9867) ingredient =

The results of the isobolographic analysis are summarized in thefollowing table 6.

TABLE 6 Experimental ED₅₀ values of the first and the secondpharmacologically active ingredient and isobolographic analysis of theinteraction between the first and the second pharmacologically activeingredient: Substance/ED₅₀ [μg/kg] (confidence interval) TheoreticalED₅₀ Experimental first second [μg/kg] of the ED₅₀ [μg/kg] ofpharmacologically pharmacologically combined the combined activeingredient active ingredient administration administration Interaction3.48 (3.07-3.89) 35267 (34433-36022) 18075 (17040-19110) 9649(9106-10137) supra- additive (p < 0.001) p: level of statisticalsignificance.

As can be seen from table 6, the experimental results are statisticallysignificant (p<0.05). Thus, synergistic effect of the first and thesecond pharmacologically active ingredient results in increasedanti-nociceptive effects.

EXAMPLE 6 First Pharmacologically Active Ingredient in Combination withRetigabine

The application route was intravenous (i.v.) for the firstpharmacologically active ingredient(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano-[3,4,b]indol]-4-aminein form of the hemicitrate salt and intraperitoneal (i.p.) for thesecond pharmacologically active ingredient retigabine dihydrochloride.The first pharmacologically active ingredient was dissolved in 5% DMSO,5% Cremophor and 90% glucose solution (5%). The second pharmacologicallyactive ingredient was dissolved in 1% CMC in aqua dest. Intraveneous(i.v.) and intraperitoneal (i.p.) applications were made in a volume of5 ml/kg.

In case of the combined, simultaneous administration, the relative doseratio of first pharmacologically active ingredient to the secondpharmacologically active ingredient was 1:1464.

When the first pharmacologically active ingredient was applied alone,the peak effect was reached 15 min p. appl. (timepoint of firstmeasurement) corresponding to an ED₅₀-value of 3.48 (3.20-3.75) μg/kgi.v. The second pharmacologically active ingredient induced adose-dependent analgesic effect with ED₅₀-values of 5088 (4677-5497)μg/kg i.p., reaching the peak effect 15 min p. appl. According to theirrespective timepoint of peak effect, the first pharmacologically activeingredient was applied simultaneously with the second pharmacologicallyactive ingredient 15 min before timepoint of measurement of theinteraction-experiments.

Thus, the time point of ED₅₀ calculation in case of the combinedadministration of the first and the second pharmacologically activeingredient according to the invention corresponds to the timepoint ofthe peak effect of the respective pharmacologically active ingredient.The isobolographic analysis revealed that the experimental ED₅₀-valuesregarding the combined administration of the first and the secondpharmacologically active ingredient were significantly lower than therespective theoretical ED₅₀-values. Thus, the combination studiesdemonstrate significant synergistic interaction of the firstpharmacologically active ingredient with the second pharmacologicallyactive ingredient.

FIG. 6 shows the graphical analysis of experimental ED₅₀-valuescorresponding to the single administration of the firstpharmacologically active ingredient and retigabine as the secondpharmacologically active ingredient, respectively, and the correspondingtheoretic additive values for the combined administration of the firstand the second pharmacologically active ingredient compared to theexperimental ED₅₀-values determined for said combination.

ED₅₀ (95% CI) [μg/kg] (i.v./i.p.) first pharmacologically activeingredient = 3.48 (3.20-3.75) second pharmacologically active ingredient= 5088 (4677-5497) theoretical additive value = 2546 (2404-2689) part offirst pharmacologically active ingredient = 1.74 (1.64-1.84) part ofsecond pharmacologically active ingredient = 2545 (2402-2687)experimental value of the combined 1404 (1316-1494) administration ofthe first and the second pharmacologically active ingredient = part offirst pharmacologically active ingredient = 0.958 (0.882-1.03) part ofsecond pharmacologically active ingredient = 1403 (1290-1516)

The results of the isobolographic analysis are summarized in thefollowing table 7.

TABLE 7 Experimental ED₅₀ values of the first and the secondpharmacologically active ingredient and isobolographic analysis of theinteraction between the first and the second pharmacologically activeingredient: Substance/ED₅₀ [μg/kg] (confidence interval) TheoreticalED₅₀ Experimental first second [μg/kg] of the ED₅₀ [μg/kg] ofpharmacologically pharmacologically combined the combined activeingredient active ingredient administration administration Interaction3.48 (3.20-3.75) 5088 (4677-5497) 2546 (2404-2689) 1404 (1316-1494)supra- additive (p < 0.001) p: level of statistical significance.

As can be seen from table 7, the experimental results are statisticallysignificant (p<0.05). Thus, synergistic effect of the first and thesecond pharmacologically active ingredient results in increasedanti-nociceptive effects.

1. A pharmaceutical composition comprising: (a) a firstpharmacologically active ingredient selected from(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-amineand the physiologically acceptable salts thereof, and (b) a secondpharmacologically active ingredient which is an anticonvulsant selectedfrom the group consisting of retigabin, lamotrigine, lacosamide,levetiracetam, carbamazepine, sultiame, phenacemide, felbamate,topiramate, pheneturide, brivaracetam, selectracetam, zonisamide,stiripentol, beclamide, mexiletin, ralfinamide, methylphenobarbital,phenobarbital, primidone, barbexaclone, metharbital, ethotoin,phenyloin, amino(diphenylhydantoin) valeric acid, mephenyloin,fosphenyloin, paramethadione, trimethadione, ethadione, ethosuximide,phensuximide, mesuximide, clonazepam, lorazepam, diazepam, clobazam,oxcarbazepine, eslicarbazepine, rufinamide, valproic acid, valpromide,γ-aminobutyric acid, progabide, tiagabine, and the physiologicallyacceptable salts thereof.
 2. The pharmaceutical composition according toclaim 1, wherein the first pharmacologically active ingredient is(1r,4r)-6′-fluoro-N,N-dimethyl-4-phenyl-4′,9′-dihydro-3′H-spiro[cyclohexane-1,1′-pyrano[3,4,b]indol]-4-aminein form of the hydrochloride, hemicitrate or maleate salt.
 3. Thepharmaceutical composition according to claim 1, wherein the secondpharmacologically active ingredient is retigabine, lamotrigine,lacosamide, levetiracetam, carbamazepine, or a physiologicallyacceptable salt thereof.
 4. The pharmaceutical composition according toclaim 1, which contains the first and the second pharmacologicallyactive ingredient in such a weight ratio that they will exert asynergistic therapeutic effect upon administration to a patient.
 5. Thepharmaceutical composition according to claim 1, wherein the relativeweight ratio of the first pharmacologically active ingredient to thesecond pharmacologically active ingredient is within the range of from1:2 to 1:1,000,000.
 6. The pharmaceutical composition according to claim1, for use in the prevention or treatment of pain, anxiety or epilepsy.7. The pharmaceutical composition according to claim 6, wherein the painis: peripheral, central or muscle skeletal pain; and/or acute, subacuteor chronic pain; and/or moderate to severe pain; and/or neuropathic orpsychogenic or nociceptive or mixed pain; and/or low back pain, visceralpain or headache; and/or post-operative, cancer or inflammatory pain. 8.A pharmaceutical dosage form comprising the pharmaceutical compositionaccording to claim
 1. 9. The pharmaceutical dosage form according toclaim 8, which contains the first pharmacologically active ingredient ina dose of from 10 to 1,200 μg.
 10. The pharmaceutical dosage formaccording to claim 8, which contains the second pharmacologically activeingredient in a dose of from 0.05 to 5 g.
 11. The pharmaceutical dosageform according to claim 8, wherein the dosage of the firstpharmacologically active ingredient is within the range of from 1:20 to20:1 of the amount which is equieffective to the dosage of the secondpharmacologically active ingredient.
 12. The pharmaceutical dosage formaccording to claim 8, which is for oral, intravenous, intraperitoneal,transdermal, intrathecal, intramuscular, intranasal, transmucosal,subcutaneous, or rectal administration.
 13. The pharmaceutical dosageform according to claim 8, which provides under in vitro conditionsimmediate release or controlled release of the first pharmacologicallyactive ingredient and/or the second pharmacologically active ingredient.14. A kit comprising a first pharmaceutical dosage form comprising thefirst pharmacologically active ingredient as defined in claim 1, and asecond pharmaceutical dosage form comprising the secondpharmacologically active ingredient as defined in claim
 1. 15. The kitaccording to claim 14, wherein the first and the second pharmaceuticaldosage form are adapted for simultaneous or sequential administration,either by the same or a different pathway of administration.